Preheat your oven to 350°F (175°C). Grease a Twinkie mold pan or mini loaf pans.
In a large bowl, cream together the butter and sugar until light and fluffy.
Add eggs one at a time, beating well after each addition. Mix in the vanilla extract.
In a separate bowl, whisk together the flour, baking powder, and salt.
Gradually add the dry ingredients to the wet mixture, alternating with milk. Mix until smooth.
Fill the molds halfway with batter and bake for 18–22 minutes or until a toothpick comes out clean. Let them cool.
In a saucepan over medium heat, combine peaches, sugar, and cinnamon. Cook until the peaches soften.
Dissolve cornstarch in water and stir into the peach mixture. Cook until thickened, about 2 minutes. Let cool.
In a small bowl, whisk together powdered sugar, milk, and vanilla extract until smooth.
Using a piping bag, fill each poundcake Twinkie with the peach cobbler filling.
Drizzle with glaze and let it set before serving.